A nearly-life-size depiction of a kangaroo — realistic genitalia included — is the oldest known rock painting in Australia. Scientists recently pinpointed its age to 17,300 years ago with a technique that had never been used on Australian ancient art before: measuring radioactive carbon in wasp nests from rocks near the artwork. 

The kangaroo painting extends across the ceiling of a rock shelter and spans nearly 7 feet (2 meters), which is roughly the height of a modern kangaroo. This and other paintings in northwestern Australia’s Kimberley region share certain stylistic features with the earliest cave art from Europe and Asia, the researchers reported. Very old animal paintings such as these are typically life-size (or close to it); they represent anatomy in a similar way, and their outlines are only partly filled-in with sketched lines. Because of these features, the paintings were thought to be among Australia’s oldest.